Histologic Study of the Esophagogastric Junction of Organ Donors Reveals Novel Glandular Structures in Normal Esophageal and Gastric Mucosae

INTRODUCTION

Whether cardiac mucosa at the esophagogastric junction is normal or metaplastic is controversial. Studies attempting to resolve this issue have been limited by the use of superficial pinch biopsies, abnormal esophagi resected typically because of cancer, or autopsy specimens in which tissue autolysis in the stomach obscures histologic findings.

METHODS

We performed histologic and immunohistochemical studies of the freshly fixed esophagus and stomach resected from 7 heart-beating, deceased organ donors with no history of esophageal or gastric disease and with minimal or no histologic evidence of esophagitis and gastritis.

RESULTS

All subjects had cardiac mucosa, consisting of a mixture of mucous and oxyntic glands with surface foveolar epithelium, at the esophagogastric junction. All also had unique structures we termed compact mucous glands (CMG), which were histologically and immunohistochemically identical to the mucous glands of cardiac mucosa, under esophageal squamous epithelium and, hitherto undescribed, in uninflamed oxyntic mucosa throughout the gastric fundus.

DISCUSSION

These findings support cardiac mucosa as a normal anatomic structure and do not support the hypothesis that cardiac mucosa is always metaplastic. However, they do support our novel hypothesis that in the setting of reflux esophagitis, reflux-induced damage to squamous epithelium exposes underlying CMG (which are likely more resistant to acid-peptic damage than squamous epithelium), and proliferation of these CMG as part of a wound-healing process to repair the acid-peptic damage could result in their expansion to the mucosal surface to be recognized as cardiac mucosa of a columnar-lined esophagus.

Histological features of gastric cardia in adults: an autopsy study

BACKGROUND AND AIMS

The existence, histology and origin of gastric cardiac mucosa are controversial. The aim of the present study was to determine the existence, histological characteristics and length of cardiac mucosa and to correlate these features with the patients' age and the presence of inflammation in the gastric cardia and/or esophagus. METHODS; The cardiac mucosa within the whole esophagogastric junction was histologically analyzed in 38 consecutive autopsy specimens and measured in 24 cases.

RESULTS

The cardiac mucosa was identified in all specimens from all cases, with a mean length of 6.7 mm, range 0.927-19.5 mm. In the majority of cases, the length of cardiac mucosa was less than 10 mm (87.5%) and greater than 5 mm (71%). Cardiac mucosa was composed of a combination of pure mucous glands and mucous glands with parietal cells in 74% of cases, and only of mucous glands with parietal cells in 26% of cases. Carditis was recorded in 23.7% cases and reflux esophagitis in 15.8%. The length of cardiac mucosa was not significantly different between cases with and without carditis (p>0.05), between those with and without esophagitis (p>0.05), and between age groups older and younger than 60 years (p>0.05).

CONCLUSION

In the adult population, a short histological segment of gastric cardia was consistently present as a normal histological structure. The type, length and circumferential presence of cardiac mucosa were not significantly associated with carditis, esophagitis or age.

Transient lower esophageal sphincter relaxations do not result from passive opening of the cardia by gastric distention

BACKGROUND & AIMS

Transient lower esophageal sphincter relaxation is the main mechanism for gastroesophageal reflux. Although there is evidence that transient lower esophageal sphincter relaxations are neurally mediated, another school of thought is that transient lower esophageal sphincter relaxations result from gastric distention, which shortens the sphincter to the point where it opens and the pressure decreases. We assessed the relationship of transient lower esophageal sphincter relaxation to gastroesophageal junction opening in an unsedated human model.

METHODS

Seven healthy volunteers (6 men and 1 woman, aged 18-53 years) were studied while they were sitting. Manometry was performed by using a sleeve catheter passed through 1 nostril. A 5.3-mm endoscope was placed through the other nostril to obtain a retroflexed view of the cardia. The biopsy channel was connected to a barostat to distend the stomach with air at 15 mm Hg for 30 minutes. Manometric and endoscopic video-recording times were synchronized but scored independently.

RESULTS

The transient lower esophageal sphincter relaxation onset invariably preceded gastroesophageal junction opening (median, 5.0 seconds; range, 0.5-20.7 seconds; P < .001). The transient lower esophageal sphincter relaxation nadir also typically occurred before gastroesophageal junction opening (median, 2.1 seconds; range, -4.2 to +19.5 seconds; P < .001). Once open, the gastroesophageal junction moved proximally for the duration of the transient lower esophageal sphincter relaxation. Termination of transient lower esophageal sphincter relaxations occurred about the time the time of gastroesophageal junction closure.

CONCLUSIONS

These data refute the hypothesis that transient lower esophageal sphincter relaxations result from passive mechanical distraction of the gastroesophageal junction. Rather, transient lower esophageal sphincter relaxations must occur before the gastroesophageal junction can open.

Endoscopic measurement of cardia circumference as an indicator of GERD

BACKGROUND

It is theorized that repeated gastric distention leads to dilatation of the cardia and the development of GERD. We hypothesize that cardia circumference correlates with the presence and the severity of GERD, and we developed software to measure cardia circumference from static endoscopic images. Our aims were to validate the software and to quantify cardia circumference along the spectrum of GERD.

METHODS

Software-based measurements were compared with actual measurements in animal and mechanical models. A retrospective review of an endoscopic database and patient charts produced 273 subjects, grouped as follows: controls, GERD, < or = 3-cm Barrett's esophagus, or > 3-cm Barrett's esophagus. A blinded abstractor measured cardia circumference by using images from the database.

RESULTS

Software and actual measurements correlated closely and were reproducible among observers. Median cardia circumference for each group was the following: control, 31.8 mm; GERD, 37.8 mm; < or = 3-cm Barrett's esophagus, 38.4 mm; and > 3-cm Barrett's esophagus, 45.0 mm (p < 0.001). By using 34.3 mm as a cutoff, cardia circumference was 85.3% sensitive and 89.6% specific for the diagnosis of GERD.

CONCLUSIONS

There was a direct relationship between cardia circumference and the presence of GERD. This finding augments our understanding of the anatomic contributions of the esophagogastric junction in the pathogenesis of GERD. Cardia measurement may prove to be a useful diagnostic tool.

Light and scanning electron microscopy of the cardiac gland region of the stomach of the Babirusa (Babyrousa babyrussa – Suidae, Mammalia)

Previous studies have indicated that the gross anatomical structure of the stomach of the babirusa (Babyrousa babyrussa) differs markedly from that of all other pigs. This light and scanning electron microscopic study revealed a previously unknown, microscopic structure characterised by a 'honeycomb' pattern at the luminal surface of the tunica mucosa. The walls of the 'honeycomb' were about 0.20-0.25 mm high and appeared almost entirely composed of various types of bacteria. Underneath the bacteria the walls were formed by thin tubes composed of non-glandular squamous epithelial-like cells, extending from the tops of the ridges between each glandular pit. There is as yet no evidence of a comparable structure in the stomach of any other pig, or to our knowledge any other forestomach-fermenting mammal.

Observations on aggregated lymphoid nodules in the cardiac glandular areas of the Bactrian camel (Camelus bactrianus)

Aggregated lymphoid nodules are an important part of the gut-associated lymphoid tissue (GALT). They are mainly distributed in the ileum and appendix of animals and humans but their distribution in the cardiac glandular area has not been reported. A study of stomach histology in the Bactrian camel has revealed that the nodules are distributed as a band-like region along the ventral wall of the stomach neck, at the beginning of the cranial enlargement and on the lesser curvature. The mucous folds are thicker in these regions than where there are no aggregated lymphoid nodules. The nodules appeared similar to ileal aggregated lymphoid nodules found in other animals and consisted of typical polymorphological lymphatic nodules arranged in a single continuous row occupying the submucosa and forming mucosal folds together with the mucous membrane. The whole mucous membrane with cardiac glands, diffuse lymphatic tissue and solitary lymphoid nodules in the lamina propria were found to cover the aggregated lymphoid nodule regions, but some nodules with a typical corona extended into the lamina propria and were covered with follicle-associated epithelium devoid of cardiac glands. These findings indicate that the stomach of the Bactrian camel possesses not only a special structure of digestion but also has characteristic immunological morphology.

On the existence and location of cardiac mucosa: an autopsy study in embryos, fetuses, and infants

BACKGROUND

The incidence of gastric cardiac adenocarcinoma has increased in the last decades. Gaining insight into the pathogenesis of this lesion is hampered by the limited knowledge of the origin and histology of cardiac mucosa (CM). Currently, the location, extent, and even the existence of CM are controversial.

AIMS

We studied the development of the gastro-oesophageal junction (GOJ) in embryos, fetuses, and infants to clarify if CM is a normal structure at birth and where it is located.

SUBJECTS

Twenty one autopsy cases were evaluated ranging in age from 13 weeks' gestational age (GA) to seven months.

METHODS

The distal oesophagus and proximal part of the stomach were embedded entirely. Serial sections were stained with haematoxylin-eosin and alcian blue/periodic acid-Schiff. The following parameters were measured: length of abdominal oesophagus; length of columnar lined oesophagus; length of CM; and distance from CM to angle of His.

RESULTS

CM was present in all evaluated sections. Its mean length varied throughout gestation. A maximum value was reached at a GA of 16 weeks (1.2 mm). After term delivery it was very short (0.3-0.6 mm). CM was proximal to, or straddled, the angle of His in all cases. During gestation, the mucin staining pattern of the CM was to a high degree similar to that of the developing pyloric mucosa.

CONCLUSIONS

CM develops during pregnancy and is present at birth as a normal structure. If the angle of His is taken as a landmark for the GOJ, CM is located in the distal oesophagus.

The gastric cardia: to be or not to be?

The origin and biologic significance of cardiac gastric mucosa are controversial. Traditionally, it has been considered native mucosa and part of normal foregut development. It has been recently suggested that cardiac mucosa is present only as a metaplastic response to gastroesophageal reflux disease and therefore always abnormal. We evaluated the esophagogastric junction in 100 pediatric autopsy samples to determine the existence, characteristics, and length of pure cardiac mucosa at different ages. No patient had a history of gastroesophageal reflux disease. Cardiac mucosa immediately distal and contiguous to the esophageal squamous mucosa was identified in all 100 samples, varying in length from 0.1 to 3 mm; the mean length was 1 mm. There was an inverse correlation between patient age and length of cardiac mucosa; gender had no influence on measured length. Three patients had mild to moderate histologic esophagitis; two had gastritis. No metaplastic features or Helicobacter pylori were identified. These findings support the concept that there is a normal, variably narrow developmental zone at the esophagogastric junction covered by cardiac mucosa and is present at birth. When cardiac type mucosa is found in biopsy material, it does not necessarily represent evidence of a mucosal metaplastic response to gastroesophageal reflux disease.

Three-dimensional pressure image and muscular structure of the human lower esophageal sphincter

BACKGROUND

The structural equivalent to the manometric high pressure zone separating the stomach from the esophagus is still a matter of dispute. We compared the three-dimensional (3D) manometric pressure image with muscular thickness and architecture at the human gastroesophageal junction.

METHODS

Three-dimensional manometric images were obtained in 25 volunteers by using a stepwise pullback technique of a catheter with eight radially oriented pressure transducers. Muscle thickness was measured in four radial directions at 10 levels between the midesophagus and stomach in 37 specimens obtained from organ donors. Muscular architecture was assessed in specimens from 10 organ donors and 12 human cadavers and was related to muscle thickness.

RESULTS

Manometric 3D images of the lower esophageal high pressure zone showed a marked radial and longitudinal asymmetry. Radial pressures peaked at the respiratory inversion point and were highest toward the left posterior direction. Anatomic evaluation showed an asymmetric thickening of the muscular layer at the gastroesophageal junction that mirrored the manometric image. Muscle thickness was highest toward the greater curvature side corresponding to the gastric "sling" fibers and toward the lesser curvature corresponding to the semicircular "clasp" fibers.

CONCLUSIONS

The human lower esophageal sphincter is not a muscular ring. Rather, the perfect match between the manometric pressures and the arrangement of muscular structures at the gastroesophageal junction indicates that the gastric sling fibers and the semicircular clasps are the anatomic correlate of the manometric lower esophageal sphincter in human beings.

[Measurement of cardia and pylorus distance by endoscopy in children]

We performed upper gastrointestinal endoscopy in 258 children. We measured the distance from the teeth to cardias and pylorus and found, that height correlated with distance from then teeth to cardias.

[Experimental study for lymphatic routes of the cardia and diaphragm]

We report discovery of the lymphatic routes in the gastric cardia and adjacent diaphragm after producing a blockage in the descending lymphatic route in dogs. CH40 black carbon hydrate was injected into the cardia portion during operation followed by total gastric and diaphragm combined resection to investigate lymphatic routes. In the 12 dogs with a blockage, and an ascending route to the lower mediastinum was recognized in 4 cases, and lateral routes from the hiatus of the esophagus to the diaphragm in a further 3 of the 12 cases. The lateral route was considered to be a collateral lymphatic route of neo-lymphatic vessel. Further, we found that phrenic lymphatic flows went in multiple directions, whereas the lymphatic flow at the phrenic lumbar vertebrae went mainly in the direction of the esophageal opening or aortic opening, although there was some expansion to the mediastinal side or celiac side. Consequently, it was assumed that metastasis to the lateral direction besides the ascending route might occur in cases with cancer in the cardiac portion infiltrating to the hiatus of the esophagus.

[The myoarchitectonics of the human gastric cardia]

Anatomical investigations of the muscular layer of the cardia in corpses of adults (30-70 years of age) have shown the presence in the cardia of a 25-35 mm long sphincter disposed at an angle to the horizontal plane. Its formation proceeds with the participation of both the esophageal musculature (circular layer) and gastric musculature (gastro-esophageal fibers of the oblique muscular layer). As a whole, myo-architectonics of the cardia is dependent on the character of interrelation of the muscular layers of the esophagus and stomach which is responsible for the opening and closure of the gastro-esophageal junction.

Number and size of perigastric lymph nodes in human adults without gastric cancer

For classification of perigastric lymph node metastases in gastric cancer, only topographical aspects are taken into consideration at present. As a numerical classification for lymph node metastases was proposed recently, the current problem is that of determining the number of dissectable perigastric lymph nodes and also assessing the quality of nodal dissection. The perigastric lymph nodes of 10 adults without gastric disease were therefore evaluated microscopically by a serial section technique. On average a total of 36.2 +/- 15.2 perigastric lymph nodes were found, e.g. 14.9 +/- 14.1 lymph nodes on the greater and 7.4 +/- 4.8 on the lesser curvature. These figures are similar to those in fetuses and newborn infants, but they exceed the numbers of perigastric lymph nodes reported in the literature for adults with or without gastric cancer. This difference could be attributable to our use of the serial section technique, because the so-called "micro-lymph nodes" with a diameter of less than 1.5 mm are consequently included in this study. Our results support the assumption, that pathologic processes do not result in any real increase of regional lymph nodes, but in an activation and enlargement of fetal lymph node reserve.

[The morphology of the cardia and the pylorus in the Chiroptera]

Organ complexes of bats (Nyctalis noctula), consisting of oesophagus, stomach and initial part of the small intestine have been subjected to histological and morphometrical investigation. As demonstrates the histological investigation of the preparations, the denticulate line of the mucous membrane of the oesophageal-gastric passage is displaced towards the stomach. In the cardia a well manifested internal sphincter has been revealed. In the place, where the stomach passes into the small intestine, on a small area of the submucosal tela of the intestine, there is an accumulation of secretory parts of the duodenal glands. They form a glandular torulus, which narrows the transitional zone lumen. A peculiarity of the bat pylorus is absence of an anatomical sphincter in it.

The anatomical location of the transesophageal echocardiographic transducer during a short-axis view of the left ventricle

This study was performed to clarify the location of a transesophageal echocardiographic (TEE) transducer when obtaining the short-axis view of the left ventricle (S-LV). The depth of the probe tip from the incisors when obtaining a S-LV, the relationship to the diaphragm, and the location of the cardia of the stomach using a gastroscope attached to the TEE probe were measured in 24 patients undergoing coronary artery bypass grafting. The location of the transducer relative to the cardia and diaphragm was determined. The study demonstrated that when obtaining a S-LV, the transducer was in the stomach in 72.7%, at the cardia in 13.6%, and in the esophagus in 13.6% of the patients. The predominantly intragastric position of the transducer suggests that gastric diseases should be included as contraindications to TEE. When the probe was advanced about 40 cm from the incisors, some resistance was often encountered by the TEE operator at about the level of the diaphragm. Careful manipulation is mandatory to avoid tissue damage by the probe. Visualization of the S-LV can be disturbed by gas in the stomach. This is a specific problem in anesthetized patients because gas is often pushed into the stomach at the time of induction.

[Quantitative microscopic characteristics of cardial glands in in the human esophagus in postnatal ontogenesis]

Microscopical investigation of oesophagus, obtained from corpses of 33 men and 33 women has been carried out (staining with hematoxylin and eosin, van Gieson). The cardial glands have been revealed in 92.4% of cases in the inferior and in 4.6% of cases in the superior third of the oesophageal wall. They have not been revealed in the superior third of the oesophageal wall. They have not been revealed in its medial third. Amount of acini in the section is essentially changeable. In elderly and old persons the ducts of the glands often form ampullar dilatations. The acinar areas on the section remain stable during the greatest++ period of the postnatal ontogenesis and only during old age they decrease slightly. The proper plate of the mucous membrane in the inferior part of the oesophagus in the zone, where the cardial glands are situated, is always thicker than in the area free from the acini. Close interrelations have been revealed between the cardial glands and lymphoid tissue of the oesophageal wall. The intensity of the glandular-lymphoid interrelations is insignificant in newborns and in children of suckling age. It is maximal in persons of mature and elderly age. Remaining at a sufficiently high level, the glandular-lymphoid associations in old persons are manifested in a less degree than in the previous age groups. No difference in organization of the cardial glands has been revealed in the superior and inferior parts of the oesophageal wall, as well as any sex peculiarities.

[Anatomo-topographic studies of the esophagogastric junction in humans]

By means of histo-topographical sections 80 preparations of the distal end of the esophagus and the cardia of the stomach have been studied. The blocks have been cut in the frontal and horizontal planes. Certain variability in thickness of the circular layer of the EGP muscle membrane has been revealed. Presence of the EGP sphincter has been proved morphologically. The maximal thickness of the EGP sphincter is observed in stomachs of the greatest dimensions and vice versa, the minimal one--in stomachs of the least dimensions. The maximal manifestation of the sphincter has been described in the preparations of the stomachs which have the form of a stocking, and the minimal--the form of a horn. The maximal manifestation of the EGP sphincter is demonstrated at 26 up to 60 years of age. The most often occurring places of the EGP sphincter localization have been determined: they are in the region of the esophageal foramen of the diaphragm and the abdominal part of the esophagus.

Ultrastructure of the peritrophic membrane-secreting cells in the cardia of the blowfly, Lucilia cuprina

Scanning and transmission electron microscopy are used to reveal the internal anatomy and ultrastructure of the cardia which is the source of the triple layered peritrophic membrane in the blowfly Lucilia cuprina. Within the cardia, rings of secretory cells (formation zones) and non-secretory tissue (valvula cardiaca) interlock to secrete and mould the layers of membrane. Formation zone cells have abundant rough endoplasmic reticulum, Golgi and secretory vesicles. A portion of midgut just posterior to the formation zone is covered by close-packed microvilli connected by septate-like junctions. The cuticle-lined valvula cardiaca is rich in smooth endoplasmic reticulum, glycogen and microtubules. The oesophageal cuticle is unusual in containing tubular structures. The ultrastructural features of the separate components of the cardia are discussed in terms of their secretory and non-secretory roles; modified midgut cells secrete chitin and protein whereas modified foregut tissue (valvula cardiaca) appears to be adapted to provide structural integrity (extensive junctions, microtubules), movement (muscles, possibly microtubules), a store of energy (glycogen deposits) and possibly a lipidic secretion (from smooth endoplasmic reticulum) to lubricate the passage of the membranes.

Sensory vagal innervation of the rat esophagus and cardia: a light and electron microscopic anterograde tracing study

Wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) was injected into nodose ganglia of rats. In the esophagus and cardia, dense networks of anterogradely labeled fibers and beaded terminal-like arborisations were observed around myenteric ganglia after combined histochemistry for HRP and acetylcholinesterase. The muscularis externa and interna proper were free of label except for a few traversing fibers. Submucosal and mucosal labeling was rather sparse except for the most oral part of the esophagus, where a dense mucosal innervation was found. Control experiments including WGA-HRP injections into the cervical vagus nerve, nodose ganglion injections after supranodose vagotomy, and anterograde [3H]leucine tracing from the nodose ganglion indicated that all labeled fibers in the esophagus and cardia originated from sensory neurons in the nodose ganglion. Electron microscopy revealed that labeled vagal sensory terminals related to myenteric ganglia were mostly large, mitochondria-rich profiles located predominantly on the surface of the ganglia. Specialized membrane contacts connected sensory terminals with other unlabeled profiles possibly derived from intrinsic neurons. The polarity of these contacts suggested the vagal sensory terminals to be presynaptic to intrinsic neurons of the myenteric ganglia. A hypothesis is formulated postulating a mechanoreceptive role for 'myenteric' vagal sensory terminals, providing both the brainstem (via the vagus nerve) and, by synaptic action upon intrinsic neurons, the myenteric plexus with information on tension and motility of the esophagus and cardia.

[Phrenico-esophageal membrane: anchoring of the terminal esophagus and cardia at the diaphragm]

The esophageal hiatus lies in the muscular part of the diaphragm. The hiatus transmits, in addition to the esophagus, the vagus nerves, the esophageal blood vessels and connective tissue. The connective tissue binding the esophagus to the diaphragm has been termed the phrenico-esophageal membrane. Its strongest part derives from the inferior diaphragmatic fascia, extends some distance above the diaphragm to attach to the adventitia of the esophagus. The variations of the attachments have been described in detail. The importance for the surgical treatment of mobilisation and a supplementary suture of the lower esophagus are discussed.

Perimeter and location of the muscular gastroesophageal junction or 'cardia' in control subjects and in patients with reflux esophagitis or achalasia

The location and perimeter of the true muscular gastroesophageal junction or cardia were determined during operation in 6 patients with achalasia, in 20 control subjects, and in 40 patients with reflux esophagitis. These two latter groups were submitted to highly selective vagotomy, owing to duodenal ulcer in the control subjects and as part of the surgical technique in reflux esophagitis patients. The careful dissection and isolation of the distal 5-6 cm of the esophagus and esophagogastric junction permitted us to measure the location and perimeter very precisely. There was a very close correlation between the distance incisors-beginning of gastroesophageal sphincter measured preoperatively and the distance incisors-cardia measured during surgery. The cardia could be clearly identified by external inspection corresponding to the limit between the longitudinal muscle layer of the esophagus and the serosal surface of the stomach. The perimeter of the cardia in the patients with reflux esophagitis was significantly larger than the perimeter of the control subjects (p less than 0.001). Intraoperative manometry demonstrated that the external limit of the cardia corresponded to the beginning of the gastroesophageal sphincter. Patients with achalasia had significantly smaller perimeter than controls or reflux esophagitis patients (p less than 0.001).

Progress in radiology: historical review of the changing concepts of lower esophageal anatomy: 430 B.C.--1977

Some of the classic studies on the anatomy of the lower esophagus are reviewed. In every case, the original sources have been consulted. The basis for a proposed anatomic description of the lower esophagus is established on the basis of the most modern research. The genesis of ideas on the anatomic nature of the cardia, phrenoesophageal membrane, esophageal pouches, esophageal sphincters, esophageal rings, gastroesophageal angle, flap valve, and cardiac notch is traced.

A simple method of determining the boundary between the antrum and corpus of the stomach. Part 2. Electric vagal stimulation in dogs

Our previous work demonstrated that electric vagal stimulation in conjunction with Congo red as a dye-indicator is the faster and more reliable method for delineating the corpus-antral boundary in rats. Based on this finding, our study was extended to a larger animal model, the dog; this study proved the electrical vagal stimulation along with Congo red is a reliable method for adequate demonstration of this corpus-antral boundary. No untoward effect on the cardiac function was observed during stimulation of subdiaphragmatic portion of vagal trunks.

Historical aspects of the anatomy of the cardia with special reference to hiatus hernia

Images